536 



MURID^— APODEMUS 



smaller size, the average (although large ones occur) being not greater 

 than in s. sylvaticus ; in its greater zygomatic and inter-orbital widths, 

 broader and deeper brain-case, and larger bullae, it" makes a still nearer 

 approach to h. hebridensis than does the Jura form. 



(5) ^. hebridensis fiolagan, Hinton. 



1914. Apodemus hebridensis fiolagan, Hinton, Ann. and Mag. Nat. //is/.,]\i\y 

 1914, 131 ; described from the island of Arran, Inner Hebrides; type specimen, 

 a male. No. 15. 5. 29.16 of the British Museum collection. 



1913. Apodemus sylvaticus sylvaticus, G. E. H. Barrett-Hamilton and M. A. C. 

 Hinton, Proc. Zool. Soc, London, 1913, 835. 



Celtic name : — (Local ; in Arran) — Fiolagan (Alston). 



Distribution : — The island of Arran, Inner Hebrides. 



Description : — This is a large mouse approaching h. hebridensis in 

 size, in which the feet and tail are rather shorter, and the ears no larger 

 than in the typical form. In colour the back is rather rufous, though 

 considerably darker than in cunibrcB ; the ventral surface is (in the 

 typical series of eight from Brodick, Arran) silver, darkened slightly by 

 the bases of the hairs, with hardly a trace of the pectoral spot ; the line of 

 demarcation is clearly defined. In a female from the cliffs near King's 

 Caves, Arran, there is a bright pectoral spot which is continued back- 

 wards as a median wash of yellow. The skull is a little smaller than 

 in h. hebridensis, though larger than in cumbrce ; its chief peculiarity is 

 the unusual lengthening of the pterygoid region, the post-molar length 

 being long, as in the skulls from Tiree and Jura, while the bullae are 

 relatively smaller than in any other sub-species of hebridensis; it 

 differs from h. hebridensis further in the slightly wider nasals, slightly 

 greater palatal length, shorter diastemata, smaller incisive foramina, 

 broader masseteric plates, and longer molar series. The differences 

 noted appear to be correlated with the greater muscular needs of a 

 rather more powerful dentition. 



DIMENSIONS IN MILLIMETRES:— 



